Brise soleil

Brise soleil, sometimes brise-soleil (French: [bʁiz sɔlɛj]; lit. 'sun breaker'), is an architectural feature of a building that reduces its heat gain by deflecting incoming sunlight. The system allows low-level sunlight to enter a building in the mornings, evenings and during winter but cuts out direct light during summer.

Brise-soleil can comprise a variety of permanent sun-shading structures, ranging from the simple patterned concrete walls popularized by Le Corbusier in the Palace of Assembly to the elaborate wing-like mechanism devised by Santiago Calatrava for the Milwaukee Art Museum or the mechanical, pattern-creating devices of the Institut du Monde Arabe by Jean Nouvel.

In the typical form, a horizontal projection extends from the sunside facade of a building. This is most commonly used to prevent facades with a large amount of glass from overheating during the summer. Often louvers are incorporated into the shade to prevent the high-angle summer sun falling on the facade, but also to allow the low-angle winter sun to provide some passive solar heating.